/Engine/Plugins/Runtime/MeshModelingToolset/Source/MeshModelingTools/Public/EditMeshPolygonsTool.h
Simplify the underlying triangulation along the selected edges, when doing so won't change the shape or UVs, or make low-quality triangles
[UFUNCTION](Programming/UnrealArchitecture/Reference/Functions)(CallInEditor, Category=EdgeEdits, Meta=(DisplayPriority=6)) void Simplify()